Apparatus for assembly of veneer sheets in plywood fabrication

ABSTRACT

First and second pneumatic pickup means include a first and a second suction duct, respectively, thereby successively to pick up veneer sheets stacked up separately on first and second lifter means. First and second conveyor means extend in succession from the first pneumatic pickup means, whereas third conveyor means extend underneath the downwardly inclined second conveyor means from the second pneumatic pickup means to a point of termination of the second conveyor means, so that the veneer sheets picked up separately by the first and the second pneumatic pickup means are superposed one upon another as they reach fourth conveyor means, from which the veneer sheets are transferred onto a stand positioned on one side thereof. Veneer sheets to be glued are stacked up separately and are fed one by one into gluing means positioned on the other side of the fourth conveyor means and thence are carried over to the aforesaid stand by fifth conveyor means.

United States Patent 1191 0on0 et al.

[54] APPARATUS FOR ASSEMBLY OF VENEER SHEETS IN PLYWOOD FABRICATION [75]Inventors: I-liroshi 0on0, Nagoya; Masanori Tamura, Aichi, both of Japan[73] Assignees: Kabushiki Kaisha Taihei Seisakusho (also known as TaiheiMachinery Works, Ltd.); Mizuho Gohan Kabushiki Kaisha, Nagoya-shi, Japan221 Filed: Feb. 23, 1971 [21] App]. No.: 117,977

[30] Foreign Application Priority Data Feb. 25, 1970 Japan ..45/18504[52] US. Cl. ..l56/557, 156/570, 156/578, 198/209 [51] Int. Cl ..B32b31/12, B65g 29/00 [56 References Cited UNITED STATES PATENTS 3,616,09010 1971 Larson ass/557 x Clausen et al. ..l56/557 X Harmsworth ..156l570X Primary ExaminerPhilip Dier Attorney-Holman & Stern [57] ABSTRACTFirst and second pneumatic pickup means include a first and a secondsuction duct, respectively, thereby successively to pick up veneersheets stacked up separately on first and second lifter means. First andsecond conveyor means extend in succession from the first pneumaticpickup means, whereas third conveyor means extend underneath thedownwardly inclined second conveyor means from the second pneumaticpickup means to a point of termination of the second conveyor means, sothat the veneer sheets picked up separately by the first and the secondpneumatic pickup means are superposed one upon another as they reachfourth conveyor means, from which the veneer sheets are transferred ontoa stand positioned on one side thereof. Veneer sheets to be glued arestacked up separately and are fed one by one into gluing'meanspositioned on the other side of the fourth conveyor means and thence arecarried over to the aforesaid stand by fifth conveyor means.

' 9 Claims, 11 Drawing Figures PATEP-HEUmaznava 3,723 ,227

SHEET 2 OF 8 PATENTEUHARZTIHTS SHEET 6 [IF .8

APPARATUS FOR ASSEMBLY OF VENEER SHEETS IN PLYWOOD FABRICATIONBACKGROUND OF THE INVENTION This invention relates generally to thefabrication of plywood and like laminated materials, and morespecifically to a novel apparatus for automatic assembly of veneersheets, both glued and nonglued sheets, into a form ready to be pressedtogether into plywood.

The assembly of glued and nonglued veneer sheets, usually in oddnumbers, into a form ready to be pressed together into plywood has longbeen the bottleneck in plywood factories, necessitating at least threeoperators attending to each gluing machine. One of them may take chargeof the glued veneer sheets fed out of the gluing machine, while at leasttwo others handle nonglued sheets. Such heavy manual labor requiredheretofore has rendered the assembly job not only unduly inefficient butalso highly dangerous. It has been accordingly impossible to carry outthe operation over any extended length of time; moreover, the veneersheets so handled manually have been inevitably liable to damage.

SUMMARY OF THE INVENTION A principal object of the present invention,therefore, resides in the provision of apparatus capable ofautomatically and continuously performing the assembly of glued andnonglued veneer sheets into a form ready to be pressed together intoplywood thereby to afford efficient and safe operation and a greatsaving in labor cost.

Another object of the invention is to provide apparatus whereby gluedand nonglued veneer sheets can be automatically assembled in a neatlyarranged form in accordance with almost any desired plywoodconstruction.

A further object of the invention is to provide apparatus for theassembly of glued and nonglued veneer sheets such that the veneer sheetsare securely guided to a final stand where they are assembled into adesired form so that they will not be damaged during operation of theapparatus.

All of these objects, as well as the additional objects and advantagesof the invention hereinafter set forth, are accomplished by the presentapparatus described succeedingly in terms of its preferred formillustrated by way of example in the accompanying drawings. 1

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. I is a side elevational view showing a preferred embodiment of thepresent invention, exclusive of gluing means, a stand, and other parts;

FIG. 2 is a schematic, side elevational view showing gluing means, astand, and other parts positioned on both sides of fourth conveyor meansof the apparatus shown in FIG. 1;

FIG. 3 is a top view showing the preferred embodiment of FIG. 1 incombination with the various means shown in FIG. 2;

FIG. 4 is an explanatory, partial, relatively enlarged side view offirst pneumatic pickup means of the apparatus shown in FIGS. 1 and 3;

FIG. 5 is a schematic, partial, relatively enlarged top view of thefirst pneumatic pickup means of FIG. 4;

FIG. 6 is an explanatory, relatively enlarged front view of the veneersheet adjusting means of the apparatus shown in FIG. 1;

FIG. 7 is a relatively enlarged top view showing the veneer sheetadjusting means of FIG. 6 in combination with part of third conveyormeans;

FIG. 8 is an explanatory, relatively enlarged front view of veneer sheettransfer means of the apparatus shown in FIGS. 1, 2 and 3;

FIG. 9 is an explanatory, relatively enlarged top view of the veneersheet transfer means of FIG. 8;

FIG. 10 is an explanatory, relatively enlarged side view of means forsupplying veneer sheets toward a pair of gluing rollers; and

FIG. 11 is a partially broken away, relatively enlarged top view of themeans of FIG. 10.

DETAILED DESCRIPTION OF THE INVENTION Referring now to FIGS. 1 and 3which illustrate elevational and plan views of the overall configurationof a preferred form of the present apparatus, as well as to FIGS. 4through 7 showing the various portions of the same in greater detail,reference numeral 1 generally designates first pneumatic pickup means.As illustrated in detail in FIGS. 4 and 5, the first pneumatic pickupmeans 1 include a first motor 2, a pair of rollers 3 with belts 4wrapped thereon to be driven by the first motor 2, a first suction duct7 coupled to an exhauster means 6 suitably mounted between beams 5 and5a and adapted for creation of a partial vacuum in the first suctionduct 7, a hydraulic cylinder 9 attached to the midpart of a horizontalportion of a frame member 8 substantially in the shape of an invertedletter U for desired vertical movements of the first suction duct 7, anda pair of pinch rollers 11 driven by a second motor 10 mounted upon thebeam 5. The first pneumatic pickup means comprising the foregoingessential components is used for the pickup and transfer, in a mannerstill to be described, of veneer sheets 12 stacked on a first lifter 13which may be powered hydraulically.

The reference numeral 14 generally designates first conveyor meanscomposed primarily of a number of rollers 16 supported by means ofbearings transversely between the frame member 8 and another identicallyshaped frame member 15. the rollers 16 have a common guide 17 at oneside thereof, these rollers I6 are driven by means of the second motor10 upon the beam 5 in synchronism with the pair of pinch rollers 11 ofthe first pneumatic pickup means 1. A first stop 18 at the end of thefirst conveyor means 14 is adapted to be moved vertically by a hydrauliccylinder 19 secured to the frame member 15 thereby to permit or preventthe passage of veneer sheets carried by the first conveyor means 14.

Disposed in succession to the first conveyor means 14, second conveyormeans 20 also include a number of rollers 22 which are supported bymeans of bearings transversely between the frame member 15 and stillanother identically shaped manner as the rollers 16 of the firstconveyor means 14. The second conveyor means 20 as a whole inclinesdownwardly as seen in FIG. 1, and, as is clear from FIG. 3, all but thelast of the rollers 22 are arranged out of the perpendicular to thelongitudinal direction of the second conveyor means in order to urge theveneer sheet being conveyed thereby against a guide 23 at one side andhence to neatly reposition the same. A second stop 24 is provided at theend of the second conveyor means 20 and is adapted to be movedvertically by a hydraulic cylinder 25 secured to the frame member 21thereby to permit or prevent the passage of the veneer sheet.

Below the first conveyor means 14 there is provided second pneumaticpickup means 34 composed primarily of a second suction duct 30, ahydraulic cylinder 31 and a pair of pinch rollers 33. The suction ductis provided with a pair of rollers 27 with belts 28 passed therearoundto be driven by a third motor 26 and is coupled to an exhauster means 29suitably mounted on the beam 5 and adapted for creation of a partialvacuum in the second suction duct 30. The hydraulic cylinder 31 issecured to the frame member 15 for causing desired vertical movements ofthe second suction duct 30. The pair of pinch rollers 33 are driven bymeans of a fourth motor 32 secured to the frame member 15. The secondpneumatic pickup means 34 of the above described arrangement is alsoused for the pickup and transfer, in a manner still to be described,

of a number of veneer sheets stacked on a second lifter 36 that may bepowered hydraulically.

Below the aforementioned second conveyor means 20, on the other hand,there is provided third conveyor means 38 comprising a number of rollers37 which are supported by means of bearings transversely between theframe members 15 and 21 and which are driven by the fourth motor 32secured to the frame member 15 in synchronism with the pair of pinchrollers 33. In addition to a guide 39, the third conveyor means 38 areprovided with adjusting means 40 as illustrated in FIG. 1 and, ingreater detail, in FIGS. 6 and 7.

With reference now specifically to FIGS. 6 and 7 for a description ofthe adjusting means 40, a wheel 44 and a plurality of large-diameterpulleys are fixedly mounted on a common shaft 43 provided on a mount 41via bearings 42. A plurality of rods 46, are interconnected with therollers 37 of the third conveyor means 38 as seen in FIG. 7, are eachcoupled at one end to the shaft 43 and provided at the other end with asmall diameter pulley 47, and a belt 48 is passed around the largediameter pulley 45 and the small diameter pulley 47 at the ends of eachrod 46. Those belts 48 are made to run in the same direction by means ofa fifth motor 49 via a chain 50 extending from the output shaft of thisfifth motor 49 to the wheel 44. The rods 46 are each rendered rockable,i.e., made capable of changing the vertical position of the free end, bymeans of a hydraulic cylinder 52 on a fixture 51 secured to the mount41.

Further, in succession to the second and the third conveyor means 20 and38, there is provided fourth conveyor means 53 on a mount 56 movable onrails 54 by means of its wheels 55. A common guide 61 and a number ofrollers 58 of the fourth conveyor means 53 are adapted to be driven by asixth motor 57 fixedly mounted on the movable mount 56. The fourthconveyor means 53 is further provided with a stop 59 at the end thereofand veneer sheet transfer means 60 still to be described in detail withreference to FIGS. 8 and 9.

Referring now to FIG. 2, a stack of veneer sheets 63 on a third lifter62 that may be powered hydraulically, and which is positioned on oneside of the fourth conveyor means 53 (refer also to FIG. 3) are fedsucces' 5 sively by means of a pair of pinch rollers 64 toward a pair ofgluing rollers 66 of gluing means generally designated by the referencenumeral 65. The veneer sheets 63 so glued are led out of the gluingmeans by fifth conveyor means 67 provided therefor onto a stand 68 onthe other side of the fourth conveyor means 53 in suitable combinationwith the nonglued veneer sheets fed by the transfer means 60 with theaid of a stop 69.

The veneer sheet transfer means 60 shown somewhat incompletely in FIGS.1 and 3 are illustrated in greater detail in FIGS. 8 and 9. The transfermeans 60 include a seventh motor 70 installed on the movable mount 56,pairs of wheels 72 and 720 both driven by the seventh motor 70 viachains 71, corresponding pairs of follower wheels 73 and 73arespectively driven by the wheels 72 and 72a via chains 74 and 74aextending therebetween, and forklift means 75 coupled to the chains 74and 74a.

The forklift means 75 include fork tines 76 arranged in aninterdigitated manner with the rollers 58 of the fourth conveyor means53, as seen in FIG. 3, and upward projections 77 close to the roots ofthe fork tines 76 thereby to press the veneer sheets from the fourthconveyor means 53 onto the stand 68. The chains 74 and 74a are providedwith chain supports 78 to prevent them from dangling down duringoperation; further, the reference numeral 79 in FIG. 9 designates chainguides adapted for regulation of the running course of the chains.

FIGS. 10 and 11 illustrate the details of the gluing means 65 of FIGS. 2and 3. A hydraulic cylinder 80 is secured to the gluing means 65 forvertical displacement of the lower roller 64a of the pair of pinchrollers 64. When the lower pinch roller 64a is lowered by the hydrauliccylinder 80, as indicated by the dots and dashes in FIG. 10, the passageof the veneer sheets 63 toward the gluing rollers 66 is blocked by astop 81. The upper pinch roller 64 is driven by an eighth motor 82.

Proceeding now to the description of the operation of this preferredembodiment of the invention of the organization substantially asdescribed hereinabove, it will be first assumed, for purposes ofillustration, that the apparatus is operated for the fabrication ofthreeply plywood, consisting of three layers of veneer. With referenceto FIG. 1, the uppermost sheet from the stack of veneer sheets 12 on thefirst lifter 13 is drawn up by the first suction duct 7. Simultaneously,its rollers 3 rotate by being driven with the first motor 2, while thefirst suction duct 7 itself together with the rollers 3 is raised bymeans of the hydraulic cylinder 9, in such a manner that the veneersheet is fed into the pair of pinch rollers 11 and thence onto the firstconveyor means 14.

The veneer sheet is thus carried along the guide 17 of the firstconveyor means 14 driven by the second motor 10 in synchronism with thepinch rollers 11, until it is stopped by means of the first stop 18.Upon elevation of this first stop 18 by the hydraulic cylinder 19secured to the frame member 15, the veneer sheet is permitted to passageonto the downwardly inclined second conveyor means 20 and is carriedthereon, while being neatly readjusted due to the combined action of therollers 22 and the guide 23 (refer also to FIG. 3), down to the secondstop 24.

Substantially at the same time with the elevation of the first stop 18by means of the hydraulic cylinder 19, the uppermost sheet from thestack of veneer sheets 35 on the second lifter 36 is drawn up by thesecond suction duct 30. Simultaneously, the pair of rollers 27 providedfor this second suction duct 30 are started in rotation by the thirdmotor 26, while the second suction duct 30 itself together with itsrollers 27 is raised by the hydraulic cylinder 31 in such a manner thatthe veneer sheet picked up thereby from the stack 35 is fed to the pairof pinch rollers 33 and thence onto the third conveyor means 38 drivenby the fourth motor 32 in synchronism with the mentioned pinch rollers33. The veneer sheet is thus carried toward the second stop 24 whilebeing subjected to the action of the adjusting means 40 in a mannerdescribed hereinbelow with reference to FIGS. 6 and 7. 1

The fifth motor 49 operates to rotate the shaft 43 via the chain 50 andthe wheel 44, so that the belts 48 extending between the large diameterpulleys 45 and the small diameter pulleys 47 are caused to run asindicated by the arrows in FIG. 6. One of the ends of each of the rods46, provided with the small diameter pulley 47, is raised by thehydraulic cylinder 52 up to a position also indicated by the dots anddashes in FIG. 6, so that the veneer sheet being carried by the thirdconveyor means 38 is neatly readjusted by being pressed against theguide 39.

Referring back to FIG. 1, the second stop 24 is then raised by thehydraulic cylinder 25, with the result that the fourth conveyor means 53driven by the sixth motor 57 takes over the conveyance of the two veneersheets, now in superposed form, that have been respectively carried bythe second conveyor means 20 and the third conveyor means 38. The veneersheets thus conveyed along the guide 61 of the fourth conveyor means 53come to a stop as their leading ends contact the stop 59.

With relation to FIGS. 8 or 9, the seventh motor 70 now comes intooperation to drive the wheels 72 and 72a via the chains 71, so that thechains 74 and 74a extending between these wheels 72 and 72a and thefollower wheels 73 and 73a start to run. As a result, the fork tines 76coupled to these chains 74 and 74a move as indicated by the arrow inFIG. 8 to a position represented by the dots and dashes in the samefigure, while carrying the superposed veneer sheets neatly positionedthereupon by means of their projections 77. As the wheels 72 and 72a andthe follower wheels 73 and 73a further rotate counterclockwise in FIG.8, the

7 overall forklift means 75 are returned to their initial position bythe chains 74 and 740 while only the superposed veneer sheets are leftupon the stand 68 with the aid of the stop 69.

The veneer sheets 63 to be glued are transferred on to the stand 68 viathe gluing means 65 as described hereinbelow with reference to FIGS. and11, in particular. When the lower roller 64a of the pair of pinchrollers 64 is lowered by means of the hydraulic cylinder 80 into theposition indicated by the dots and dashes in FIG. 10, the uppermostsheet of the stack of veneer sheets 63 fed into the gluing means 65 isblocked by the stop 81. It is accordingly necessary or at leastpreferable, by a photoelectric tube, a limit switch or some otherappropriate means not illustrated in the drawings, to detect thecompletion of the mounting of the superposed veneer sheets on the stand68 by the forklift means and simultaneously to actuate the hydrauliccylinder under the control of such detecting means. The lower pinchroller 64a is then raised to permit the passage of one of the veneersheets 63 between the gluing rollers 66 of the gluing means 65. Theveneer sheet thus glued is led out of the gluing means 65 onto the fifthconveyor means 67 and thence onto the superposed veneer sheetsprecedingly placed upon the stand 68.

Hence, by alternately placing two nonglued veneer sheets in superimposedposition, a single glued veneer sheet and then two nonglued veneersheets in superposition upon the stand 68, one of the two first-placednonglued veneer sheets, the single second-placed glued veneer sheet andone of the two third-placed nonglued veneer sheets constitute the twofaces and one core necessary for the fabrication of a desired three-plyplywood sheet.

For the fabrication of five-ply plywood, the following feeding of theveneer sheets are successively carried out in the same manner as that inthe case of fabricating three-ply plywood. That is, a non-glued veneersheet is fed unto the stand 68, a first glued veneer sheet is fed ontothe veneer sheet placed on the stand 68, a nonglued veneer sheet is fedonto the first glued veneer sheet, a second glued veneer sheet is fedonto the nonglued sheet, and a non-glued veneer sheet is fed onto thesecond glued veneer sheet whereby a desired five- -ply plywoodconsisting of two outside sheets a central sheet, and two sheetsdisposed respectively between the central sheet and the outside sheetsis obtained.

The fourth conveyor means 53 and the transfer means 60 are provided uponthe movable mount 56 for the sake of convenience in removal of glue oradhesive that may adhere to the fifth conveyor means 67 extending fromthe gluing means 65. Further, the operations of the hydraulic cylinders9, 19, 25, 31, 52 and 80 are assumed to be carried out under the controlof the aforementioned photoelectric tube, limit switch, or othersuitable means (not shown) provided for the transfer means-60.

The preferred form of the present apparatus shown and described in theforegoing is meant only to illustrate and not to limit the invention.For instance, instead of the provision of the adjusting means 40 for thethird conveyor means 38, the rollers 37 of the third conveyor means maybe arranged out of the perpendicular to the guide 39 similarly as therollers 22 of the second conveyor means 20, while the third conveyormeans 38 as a whole are inclined downwardly also as in the secondconveyor means 20. The above and other possible modifications of theapparatus which are readily apparent to those skilled in the art arecontemplated as being within the scope of the present invention.

We claim:

1. Apparatus for assembly of veneer sheets into a form ready to bepressed togehther into plywood, comprising in combination:

first pneumatic pickup means including a first suction duct capable ofpicking up one-by-one veneer sheets stacked on a first lifter providedunder said pick-up means by virtue of a partial vacuum created therein:

first conveyor means comprising a number of rollers adapted forreceiving and conveying the veneer sheet picked up by said firstpneumatic pickup means, and first stop means provided at the end of saidfirst conveyor means opposite to said first pneumatic pickup means andadapted for transferring the veneer sheet onto a following secondconveyor means;

second conveyor means positioned in succession to said first conveyormeans and inclined downwardly along the length thereof, said secondconveyor means comprising a number of rollers adapted for receiving andconveying the veneer sheet supplied from said first conveyor means viasaid first stop means, and second stop means provided at the end of saidsecond conveyor means opposite to said first conveyor means and adaptedfor transferring the veneer sheet carried by said second conveyor meansonto a following fourth conveyor means;

second pneumatic pickup means positioned underneath said first conveyormeans and including a second suction duct capable of picking upone-byone veneer sheets stacked on a second lifter disposed under saidsecond pickup means by virtue of a partial vacuum created therein;

third conveyor means positioned below said second conveyor means andcomprising a number of rollers adapted for receiving and conveying theveneer sheet picked up by said second pneumatic pickup means, said thirdconveyor means terminating at substantially the same point as saidsecond conveyor means so that said second stop means of said secondconveyor means is used also for transferring the veneer sheet carried bysaid third conveyor means on the following fourth conveyor means;

fourth conveyor means positioned in succession to said second conveyormeans and said third conveyor means and comprising a number of rollersadapted for receiving and conveying the veneer sheets supplied from saidsecond conveyor means and said third conveyor means via said second stopmeans, and third stop means provided at the end of said fourth conveyormeans opposite to said second and third conveyor means;

transfer means adapted to transfer the veneer sheets from said fourthconveyor means onto a stand positioned on one side of said fourthconveyor means;

a third lifter mounting thereon a stack of the veneer sheets andpositioned on the other side of said fourth conveyor means;

gluing means provided between said third lifter and said fourth conveyormeans and including a pair of gluing rollers and pinch rollers adaptedto transfer a veneer sheet supplied from said third lifter into saidgluing rollers and;

fifth conveyor means extending from said gluing means and comprising anumber of rollers adapted to convey the glued veneer sheet led out fromsaid gluing means onto said stand in such a relation that nongluedveneer sheets are superimposed on both glued surfaces of the gluedveneer sheet.

2. The apparatus as claimed in claim 1, in which said first pneumaticpickup means further comprises a hydraulic cylinder coupled to saidfirst suction duct for moving the same, and a pair of belted rollerspositioned at the open end of said first suction duct.

3. The apparatus as claimed in claim 2, additionally comprising a pairof pinch rollers interposed between said first suction duct and saidfirst conveyor means, whereby the veneer sheet picked up by said firstpneumatic pickup means is fed onto said first conveyor means via saidpair of pinch rollers.

4. The apparatus as claimed in claim 1, in which said first stop meansof said first conveyor means and said second stop means of said secondand said third conveyor means are actuatable by means of hydrauliccylinders.

5. The apparatus as claimed in claim 1, in which said rollers of saidsecond conveyor means are arranged out of the perpendicular to a guideextending lengthwise at one side of said second conveyor means wherebythe veneer sheet being conveyed by the same in urged against said guideand hence is neatly readjusted thereon.

6. The apparatus as claimed in claim 1, in which said second pneumaticpickup means further comprises a hydraulic cylinder coupled to saidsecond suction duct for moving the same, and a pair of belted rollerspositioned at the open end of said second suction duct.

7. The apparatus as claimed in claim 6, additionally comprising a pairof pinch rollers interposed between said second suction duct and saidthird conveyor means, whereby the veneer sheet picked up by said secondpneumatic pickup means is fed onto said third conveyor means via saidpair of pinch rollers.

8. The apparatus as claimed in claim 1, in which said third conveyormeans is provided with means for adjusting of the veneer sheet beingconveyed thereby, said adjusting means comprising a plurality of largediameter pulleys fixedly mounted on a common shaft, a plurality of rodsinterconnected with the rollers of the third conveyor means, each ofsaid rods being rockably coupled at one end thereof to said common shaftand provided at the other end with a small diameter pulley and beltsrespectively extending between said large and said small diameterpulleys, and adapted for urging the side edge of the veneer sheet onsaid third conveyor means against a guide extending lengthwise at oneside thereof.

9. The apparatus as claimed in claim 1, in which said transfer meanscomprise a plurality of first pairs of wheels, a plurality of secondpairs of wheels respectively corresponding to said first pairs of wheelsand being driven thereby via chains extending therebetween, and forkliftmeans coupled to said chains so as to be movable along with the runthereof, said forklift means including fork tines arranged substantiallyin an interdigitated manner with said rollers of said fourth conveyormeans and upward projections formed near the roots of said fork tinesthereby to press the veneer sheets onto said stand positioned on oneside of the fourth conveyor means.

1. Apparatus for assembly of veneer sheets into a form ready to be pressed togehther into plywood, comprising in combination: first pneumatic pickup means including a first suction duct capable of picking up one-by-one veneer sheets stacked on a first lifter provided under said pick-up means by virtue of a partial vacuum created therein: first conveyor means comprising a number of rollers adapted for receiving and conveying the veneer sheet picked up by said first pneumatic pickup means, and first stop means provided at the end of said first conveyor means opposite to said first pneumatic pickup means and adapted for transferring the veneer sheet onto a following second conveyor means; second conveyor means positioned in succession to said first conveyor means and inclined downwardly along the length thereof, said second conveyor means comprising a number of rollers adapted for receiving and conveying the veneer sheet supplied from said first conveyor means via said first stop means, and second stop means provided at the end of said second conveyor means opposite to said first conveyor means and adapted for transferring the veneer sheet carried by said second conveyor means onto a following fourth conveyor means; second pneumatic pickup means positioned underneath said first conveyor means and including a second suction duct capable of picking up one-by-one veneer sheets stacked on a second lifter disposed under said second pickup means by virtue of a partial vacuum created therein; third conveyor means positioned below said second conveyor means and comprising a number of rollers adapted for receiving and conveying the veneer sheet picked up by said second pneumatic pickup means, said third conveyor means terminating at substantially the same point as said second conveyor means so that said second stop means of said second conveyor means is used also for transferring the veneer sheet carried by said third conveyor means on the following fourth conveyor means; fourth conveyor means positioned in succession to said second conveyor means and said third conveyor means and comprising a number of rollers adapted for receiving and conveying the veneer sheets supplied from said second conveyor means and said third conveyor means via said second stop means, and third stop means provided at the end of said fourth conveyor means opposite to said second and third conveyor means; transfer means adapted to transfer the veneer sheets from said fourth conveyor means onto a stand positioned on one side of said fourth conveyor means; a third lifter mounting thereon a stack of the veneer sheets and positioned on the other side of said fourth conveyor means; gluing means provided between said third lifter and said fourth conveyor means and including a pair of gluing rollers and pinch rollers adapted to transfer a veneer sheet supplied from said third lifter into said gluing rollers and; fifth conveyor means extending from said gluing means and comprising a number of rollers adapted to convey the glued veneer sheet led out from said gluing means onto said stand in such a relation that nonglued veneer sheets are superimposed on both glued surfaces of the glued veneer sheet.
 2. The apparatus as claimed in claim 1, in which said first pneumatic pickup means further comprises a hydraulic cylinder coupled to said first suction duct for moving the same, and a pair of belted rollers positioned at the open end of said first suction duct.
 3. The apparatus as claimed in claim 2, additionally comprising a pair of pinch rollers interposed between said first suction duct and said first conveyor means, whereby the veneer sheet picked up by said first pneumatic pickup means is fed onto said first conveyor means via said pair of pinch rollers.
 4. The apparatus as claimed in claim 1, in which said first stop means of said first conveyor means and said second stop means of said second and said third conveyor means are actuatable by means of hydraulic cylinders.
 5. The apparatus as claimed in claim 1, in which said rollers of said second conveyor means are arranged out of the perpendicular to a guide extending lengthwise at one side of said second conveyor means whereby the veneer sheet being conveyed by the same in urged against said guide and hence is neatly readjusted thereon.
 6. The apparatus as claimed in claim 1, in which said second pneumatic pickup means further comprises a hydraulic cylinder coupled to said second suction duct for moving the same, and a pair of belted rollers positioned at the open end of said second suction duct.
 7. The apparatus as claimed in claim 6, additionally comprising a pair of pinch rollers interposed between said second suction duct and said third conveyor means, whereby the veneer sheet picked up by said second pneumatic pickup means is fed onto said third conveyor means via said pair of pinch rollers.
 8. The apparatus as claimed in claim 1, in which said third conveyor means is provided with means for adjusting of the veneer sheet being conveyed thereby, said adjusting means comprising a plurality of large diameter pulleys fixedly mounted on a common shaft, a plurality of rods interconnected with the rollers of the third conveyor means, each of said rods being rockably coupled at one end thereof to said common shaft and provided at the other end with a small diameter pulley and belts respectively extending between said large and said small diameter pulleys, and adapted for urging the side edge of the veneer sheet on said third conveyor means against a guide extending lengthwise at one side thereof.
 9. The apparatus as claimed in claim 1, in which said transfer means comprise a plurality of first pairs of wheels, a plurality of second pairs of wheels respectively corresponding to said first pairs of wheels and being driven thereby via chains extending therebetween, and forklift means coupled to said chains so as to be movable along with the run thereof, said forklift means including fork tines arranged substantially in an interdigitated manner with said rollers of said fourth conveyor means and upward projections formed near the roots of said fork tines thereby to press the veneer sheets onto said stand positioned on one side of the fourth conveyor means. 